Acoustical and Psychoacoustic Properties for Mono Sound Walk

  • Understand acoustical properties affecting distance perception.
  • Learn psychoacoustic cues to simulate depth and movement.
  • Apply sound design techniques in the Mono Sound Walk project.
  • Explore practical strategies for spatial simulation in mono sound.

Automation Review

Let’s find a walking tour video to use for these examples.

Acoustical Properties of Distance Perception

  • Sound level (intensity) decreases with distance.
  • High frequencies attenuate faster over distance.
  • Reverberation increases in enclosed spaces.
  • Direct-to-reverberant ratio affects distance perception.

Sound Level (Intensity)

  • Sound intensity decreases by 6 dB per doubling of distance.
  • Quieter sounds suggest greater distance.
  • Use volume automation to simulate sound proximity.

REAPER Automation Envelope Shapes

  • Linear → Corresponds to Linear
  • Square → No direct counterpart (instant step)
  • Slow Start/End → Corresponds to S-Curve
  • Fast Start → Corresponds to Exponential Growth

REAPER’s Fast End and Bezier Envelopes

  • Fast End → Corresponds to Exponential Decay (Similar to Logarithmic)
  • Bezier → Customizable (Linear, Logarithmic, Exponential, or S-Curve)
    • Bezier allows full control over transitions
    • Great for detailed audio shaping

Volunteer to try volume automation?

Frequency Response (High-Frequency Roll-off)

  • High frequencies attenuate faster than low frequencies.
  • Distant sounds lose high frequencies, creating a “muffled” effect.
  • Use low-pass filtering to replicate distant sounds.

Volunteer to try low-pass filtering?

Reverberation and Echoes

  • Reverberation increases with distance in enclosed spaces.
  • A higher reverb level implies greater distance from the sound source.
  • Adjust reverb to reflect environmental conditions.

Simulating Distance with Reverb

  • Near sounds: minimal reverb, dry sound.
  • Far sounds: higher reverb, muffled sound.
  • Adjust wet/dry ratio to simulate depth.
  • EQ changes for high and low frequencies.

Starting Reverb Settings for Distance

  • Close proximity: Short reverb time, low wet/dry mix.
  • Medium distance: Moderate reverb, slight high-frequency damping.
  • Far distance: Long reverb, heavy high-frequency roll-off.
  • Adjust pre-delay for spatial reflection.

Advanced Automation: Tail and Pre-delay

  • Tail length: Adjust reverb tail for room size.
  • Pre-delay: Automate for proximity changes.
  • Combine wet/dry and pre-delay for complex depth.
  • Simulate large spaces with longer reverb tails.

Volunteer to try reverb?

Practice Tips for Simulating Distance with Echo or Delay Automation

  • Use echo/delay to create a sense of distance
  • Adjust delay time for close or distant effects
  • Modify feedback to simulate multiple reflections
  • Combine delay with reverb for natural depth

Suggested Starting Settings for Delay Automation

  • For close proximity (1-3 meters): 10-50 ms delay, 10-20% feedback
  • For medium distance (3-10 meters): 50-150 ms delay, 30-40% feedback
  • For long distance (10+ meters): 200-500 ms delay, 50-80% feedback
  • Automation curves: adjust for linear or fast changes

Volunteer to try delay?

Motion and Dynamic Cues

  • Changing sound level or frequency suggests movement.
  • The Doppler effect simulates pitch changes as sound moves.
  • Adjust sound properties dynamically to reflect movement.

Volunteer to try Doppler effect?